image-js/src/image/transform/rotate.js

Image processing and manipulation in JavaScript

import Image from '../Image';

import rotateFree from './rotateFree';

/**
 * Rotates an image.
 * @memberof Image
 * @instance
 * @param {number} angle - Angle of the rotation in degrees
 * @param {object} [options]
 * @param {InterpolationAlgorithm} [options.interpolation='nearestNeighbor'] - Interpolation algorithm to use if `angle` is not a multiple of 90
 * @return {Image} The new rotated image
 */
export function rotate(angle, options) {
  this.checkProcessable('rotate', {
    bitDepth: [1, 8, 16],
  });
  if (typeof angle !== 'number') {
    throw new TypeError('angle must be a number');
  }

  if (angle < 0) {
    angle = Math.ceil(-angle / 360) * 360 + angle;
  }

  switch (angle % 360) {
    case 0:
      return this.clone();

    case 90:
      return rotateRight.call(this);

    case 180:
      return rotate180.call(this);

    case 270:
      return rotateLeft.call(this);

    default:
      return rotateFree.call(this, angle, options);
  }
}
/**
 * Rotates an image counter-clockwise
 * @memberof Image
 * @instance
 * @return {Image} The new rotated image
 */

export function rotateLeft() {
  if (this.bitDepth === 1) {
    const newImage = new Image(this.height, this.width, {
      kind: 'BINARY',
      parent: this,
    });

    const newMaxHeight = newImage.height - 1;

    for (let i = 0; i < this.height; i++) {
      for (let j = 0; j < this.width; j++) {
        if (this.getBitXY(j, i)) {
          newImage.setBitXY(i, newMaxHeight - j);
        }
      }
    }

    return newImage;
  } else {
    const newImage = Image.createFrom(this, {
      width: this.height,
      height: this.width,
    });

    const newMaxHeight = newImage.height - 1;

    for (let i = 0; i < this.height; i++) {
      for (let j = 0; j < this.width; j++) {
        for (let k = 0; k < this.channels; k++) {
          newImage.setValueXY(i, newMaxHeight - j, k, this.getValueXY(j, i, k));
        }
      }
    }

    return newImage;
  }
}
/**
 * Rotates an image clockwise
 * @memberof Image
 * @instance
 * @return {Image} The new rotated image
 */

export function rotateRight() {
  if (this.bitDepth === 1) {
    const newImage = new Image(this.height, this.width, {
      kind: 'BINARY',
      parent: this,
    });

    const newMaxWidth = newImage.width - 1;

    for (let i = 0; i < this.height; i++) {
      for (let j = 0; j < this.width; j++) {
        if (this.getBitXY(j, i)) {
          newImage.setBitXY(newMaxWidth - i, j);
        }
      }
    }

    return newImage;
  } else {
    const newImage = Image.createFrom(this, {
      width: this.height,
      height: this.width,
    });

    const newMaxWidth = newImage.width - 1;

    for (let i = 0; i < this.height; i++) {
      for (let j = 0; j < this.width; j++) {
        for (let k = 0; k < this.channels; k++) {
          newImage.setValueXY(newMaxWidth - i, j, k, this.getValueXY(j, i, k));
        }
      }
    }

    return newImage;
  }
}

function rotate180() {
  if (this.bitDepth === 1) {
    const newImage = new Image(this.width, this.height, {
      kind: 'BINARY',
      parent: this,
    });

    const newMaxWidth = newImage.width - 1;
    const newMaxHeight = newImage.height - 1;

    for (let i = 0; i < this.height; i++) {
      for (let j = 0; j < this.width; j++) {
        if (this.getBitXY(j, i)) {
          newImage.setBitXY(newMaxWidth - j, newMaxHeight - i);
        }
      }
    }

    return newImage;
  } else {
    const newImage = Image.createFrom(this);

    const newMaxWidth = newImage.width - 1;
    const newMaxHeight = newImage.height - 1;

    for (let i = 0; i < this.height; i++) {
      for (let j = 0; j < this.width; j++) {
        for (let k = 0; k < this.channels; k++) {
          newImage.setValueXY(
            newMaxWidth - j,
            newMaxHeight - i,
            k,
            this.getValueXY(j, i, k),
          );
        }
      }
    }

    return newImage;
  }
}